TOLIS Group Knowledge Base

Tape Drive Performance Figures

Quite often, people purchase a new backup application with the idea that it will help them improve the throughput of data between their system and their backup device. Quite often, however, they are disappointed to discover that the new application is no faster than tar or cpio. The reason for this usually relates directly to the performance of the backup device they are using.

For example, an old 60MB 1/4" tape drive only accepts data at a rate of around 100 kilobytes per second. Therefore, the user should not expect more than around 6 megabytes per minute of data backed up to the tape. On even the slowest i386 running SCO XENIX, you can stream this device with tar, so buying a new backup application will not improve the speed of the backup process. Here are a few standard I/O rates for the more common backup devices available today and projected numbers for the technology as it developes.

Tape Drive Type & Connection

Native Tape Capacity

Native Transfer Rate Per Second

Native Transfer Rate Per Minute

1/4" Cartridges (DC 6000)**

With QIC-02 Interface Card

QIC-24/120/150

60.0, 125.0, 150.0, 250.0 MB

100.0 KB/s

6.0 MB/Min

With SCSI (QIC-104) Interface Card

QIC-24/120/150**

60.0, 125.0, 150.0, 250.0 MB

120.0 KB/s

7.2 MB/Min

QIC-525**

525.0 MB

230.0 KB/s

14.0 MB/Min

QIC-1000**

1.0 GB

200.0 KB/s

12.0 MB/Min

QIC-1350**

1.35 GB

600.0 KB/s

36.0 MB/Min

1/4" Floppy Tape Drives (DC 2000)**

On Standard Floppy Controller

17.0 KB/s

1.0 MB/Min

On High Speed Floppy Controller

80.0 KB/s

4.8 MB/Min

Travan Tape Drives - 8mm**

TR-4 ATAPE/IDE Interface**

4.0 GB

400.0 KB/s

28.0 MB/Min

TR-4 (NS-8) SCSI Interface**

4.0 GB

600.0 KB/s

36.0 MB/Min

TR-5 ATAPE/IDE Interface

10.0 GB

1.0 MB/s

60.0 MB/Min

TR-5 (NS-20) SCSI Interface**

10.0 GB

2.0 MB/s

120.0 MB/Min

Digital Data Storage (DDS)/Digital Audio Tape (DAT)(SCSI)

DDS-1†

2.0 GB

183.0 KB/s

11.0 MB/Min

DDS-2†

4.0 GB

500.0 KB/s

3.0 MB/Min

DDS-3†

12.0 GB

1.0 MB/s

60.0 MB/Min

DDS-4

20.0 GB

3.0 MB/s

180.0 MB/Min

DAT 72

36.0 GB

3.0 MB/s

180.0 MB/Min

DAT-160

80.0 GB

5.0 MB/s

300.0 MB/Min

DAT-320

160 GB

12.0 MB/s

720.0 MB/Min

Variable Speed Architecture (VXA) 1**

SCSI Interface

12.0, 20.0, 33.0 MB

3.0 MB/s

180.0 MB/Min

ATAPI Interface (Non-DMA)

12.0, 20.0, 33.0 MB

1.2 MB/s

720.0 MB/Min

ATAPE Interface (DMA-2)

12.0, 20.0, 33.0 MB

3.0 MB/s

180.0 MB/Min

Variable Speed Architecture (VXA) 2**

SCSI Interface

20.0, 40.0, 60.0, 80.0 GB

6.0 MB/s

360.0 MB/Min

FireWire 400

20.0, 40.0, 60.0, 80.0 GB

6.0 MB/s

360.0 MB/Min

FireWire800

20.0, 40.0, 60.0, 80.0 GB

6.0 MB/s

360.0 MB/Min

Variable Speed Architecture (VXA) 172 & 320**

VXA-172 (SCSI)

40.0, 86.0 GB

12.0 MB/s

720.0 MB/Min

VXA-320 (SCSI)

40.0, 86.0, 160.0 GB

12.0 MB/s

720.0 MB/Min

8mm Exabyte Mammoth(SCSI)**

EXB-8200/8205

2.3 GB

255.0 KB/s

15.0 MB/Min

EXB-8500/8505

5.0 GB

500.0 KB/s

30.0 MB/Min

MAMMOTH 2

25.0 GB

12.0 MB/s

720.0 MB/Min

Advanced Intelligent Tape (AIT)**

AIT-E Turbo

20.0 GB

6.0 MB/s

360.0 MB/Min

AIT-1

35.0 GB

4.0 MB/s

240.0 MB/Min

AIT-1 Turbo

40.0 GB

6.0 MB/s

360.0 MB/Min

AIT-2

50.0 GB

6.0 MB/s

360.0 MB/Min

AIT-2 Turbo

80.0 GB

12.0 MB/s

720.0 MB/Min

AIT-3

100.0 GB

12.0 MB/s

720.0 MB/Min

AIT-3 Ex

150.0 GB

18.0 MB/s

1.08 GB/Min

AIT-4

200.0 GB

24.0 MB/s

1.44 GB/Min

AIT-5

400.0 GB

24.0 MB/s

1.44 GB/Min

Super Advanced Intelligent Tape (SAIT**

SAIT-1

500.0 GB

30.0 MB/s

1.80 GB/Min

SAIT-2

800.0 GB

45 MB/s

2.70 GB/Min

Digital Linear Tape (DLT)**

DLT

2.0, 6.0, 10.0 GB

800.0 KB/s

64.0 MB/Min

DLT 4000

20.0 GB

1.5 MB/s

72.0 MB/Min

DLT 7000

35.0 GB

3.5 MB/s

210.0 MB/Min

DLT 8000

40.0 GB

4.0 MB/s

240.0 MB/Min

DLT-1 (VS80)

40.0 GB

3.0 MB/s

180.0 MB/Min

DLT-1 (VS160)

80.0 GB

8.0 MB/s

480.0 MB/Min

DLT-V4

160.0 GB

10.0 MB/s

600.0 MB/Min

Super DLT 220

110.0 GB

11.0 MB/s

660.0 MB/Min

Super DLT 320

160.0 GB

16.0 MB/s

960.0 MB/Min

Super DLT 600

300.0 GB

36.0 MB/s

2.16 GB/Min

DLT-S4

800.0 GB

60.0 MB/s

3.6 GB/Min

Linear Tape-Open (LTO )

LTO-1

100.0 GB

15.0 MB/s

900.0 MB/Min

LTO-2

200.0 GB

30.0 MB/s

1.8 GB/Min

LTO-3

400.0 GB

60 to 80.0 MB/s

3.6 to 4.8 GB/Min

LTO-4

800.0 GB

80 to 120 MB/s

4.8 to 7.2 GB/Min

LTO-5

1.5 TB

140 MB/s

8.4 GB/Min

LTO-6

2.5 TB

160 MB/s

9.6 GB/Min

LTO-7*

4.0 TB

240 MB/s

14.4 GB/Min

LTO-8*

12.8 TB

472 MB/s

28.32 GB/Min

Note: All numbers are based on the values reported by the manufacturer.

*This technology has not yet been developed or is currently under development. These statistics are the expected specifications according to the technology road map created by its developer(s).

** This technology is been officially considered End-Of-Life by its developer(s). The tape technology is no longer being developed.

† This tape generation has been officially considered End-Of-Life by its developer(s) or is no longer being manufacturered. Newer generations of the technology are still be available. The techology is still being developed.

Does This Mean I Can't Go Faster?

Actually, it probably does. If you are running a high-end system like a Sun SparcServer 10000 with Fiber Channel drives and a DDS-2 DAT with no compression, you're probably already maxing the drive out at the rated 366KB/s. Even lower performance x86 platforms can drive a tape at that speed.

If, however, you have a high-end Exabyte mechanism or a new DLT or LTO drive, you may be able to eek a few more KB/s out of the system by using a better buffering scheme or using a utility like BRU that provides double buffered I/O. With double buffered I/O, BRU fills one buffer while another is being written to tape. This way, your system maintains a steady stream of data to the backup device.